A contractor employs 20 male, 15 female and 5 children in his factory. Male wages are Rs. 10 per day, female Rs. 8 per day, and children Rs. 3 per day. The weighted x of wages paid per day will be________?

The mathematical exception of x + y is equal to ________?

Class mark is the value which divides a class into ________ equal parts?

If E(x) is the expected value of X then E[x – E(x)]= ________?

In w.o.r 2σx=________?

f1x12 + f2x22 + —————+ fxx42=________?